This invention was made in the course of, or under, a contract with the United States Department of Energy with support by the RANN Division of the National Science Foundation.
a. Field of the Invention
The invention relates to a light source for Zeeman atomic absorption spectroscopy.
b. Prior Art
One of the most difficult problems associated with Zeeman atomic absorption spectrophotometer is finding a light source which operates in a strong magnetic field for refractory and volatile elements. In spite of the powerful features of the Zeeman atomic absorption spectrophotometer, rapid acceptance has been delayed because of the light source problem.
Prior Zeeman atomic absorption spectrophotometers are described in U.S. Pat. Nos. 3,811,788; 3,914,054 and 3,957,375.
Originally, specially designed electrodeless discharge lamps (EDL) were used for Zeeman atomic absorption spectrophotometer for elements such as Hg, Cd, As, Se, Zn and Pb in a strong magnetic field. However, in spite of a development effort, the electrodeless discharge lamp failed to operate reliably with most of the refractory elements. Thus, it was apparent that if Zeeman atomic absorption spectrometry was to be accepted as a usable tool for elemental analysis, a new light source which operates more reliably must be developed.
In general, for atomic absorption spectrophotometry, hollow cathode lamps are used for refractory elements and recently, electrodeless discharge lamps are used for volatile elements. The conventional hollow cathode lamps and electrodeless discharge lamps do not operate well in a presence of a high magnetic field, which is used in Zeeman spectroscopy.